1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor device.
2. Related Background Art
In recent semiconductor devices, structures thereof are extremely complicated to achieve miniaturization and an improvement in device performance, and the number of steps to manufacture the devices is thereby precipitously increased. Therefore, reducing the number of steps as much as possible to decrease a manufacturing cost is a very important problem in manufacture of semiconductor devices.
In miniaturization processing, especially a dry etching process, there is collective processing as a technique that is effective for a reduction in cost. According to this technique, processing that has conventionally been carried out in different reaction chambers at a plurality of steps is continuously performed in one reaction chamber. According to the collective processing, since a time required for loading/unloading with respect to the reaction chamber is simply reduced to ½ and a throughput of each unit with respect to this step is greatly improved, the number of units can be reduced, and a cost can be readily decreased.
On the other hand, when the collective processing is carried out in the dry etching process, a deposition film is formed on an inner wall of the reaction chamber due to a reactive gas used in previous processing. In the general dry etching process, cleaning processing of removing such a deposition film is appropriately carried out (see, e.g., Japanese Patent laid open (kokai) 2006-019626), but the processing advances to the next step without removing such a deposition in the collective processing. In such a case, substrate scraping or shoulder abrasion of a mask material occurs due to an effect of the deposition that has adhered to the inner wall of the reaction chamber, which becomes a factor of degrading device characteristics.
As explained above, continuously performing different types of processing as the collective processing in the dry etching process is very difficult.